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Answer briefly : (a) How do you percei...

Answer briefly :
(a) How do you perceive the colour of an object ?
(b) Which part of our body helps us in maintaining the body balance ?
(c) How does the eye regulate the amount of light that falls on the retina.

Text Solution

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(a) In retina of human eye, there are types of cones having their own peculiar photopigments e.g., chlorlabs, cyanolabs and erythrolabs which perceive green, blue and red radiations. Other colours are detected by simultaneous stimulation of more than one type of cones e.g., yellow colour is perceived when green and red cones are stimulated approximately in equal numbers.
(b) Cristae present in the ampullae of semicircular canals of internal ear control static equilibrium (when body at rest) and linear acceleration (rapid forward movements)
(c) By regulating the size of pupil of iris with the help of two sets of iridial muscles : circularly arranged sphincter muscles decrease the size of pupil in bright light, while radilly arranged dilator muscles increase the size of pupil in dim light.
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